The present invention relates generally to the field of Internet telephony, and more particularly to a method of and system for providing quality of service in an Internet telephony session.
Two trends are currently occurring in the telecommunications marketplace. First, telephony services are being added to Internet protocol-based devices. Second, Asynchronous Transfer Mode (ATM) networks are being built with the ability to support user specified quality of service (QoS) on a per connection basis, as part of the ATM switched virtual circuit service capability.
Each of these trends have problems. The primary problem with the introduction of telephony services to the IP network is one providing predictable QoS on a per call/connection basis. Although technologies are being developed in the Internet community to address this problem, there is currently no way to guarantee QoS on a per connection basis through an IP network. The primary problem with the second trend is not one of basic service capability, but is rather one of access to the service. Today virtually all desktop devices have access to an IP network through some sort of local area network technology, for example through Ethernet. The problem is that these desktop devices generally do not have access to ATM networks that provide the per call/connection guarantee QoS.
The primary method of addressing QoS in the current IP-BASED networks is to over-provision the amount of bandwidth available in the network. This approach will work as long as the usage of the network stays within the bounds of the available bandwidth. If the usage of the network is not predictable, then it is difficult, for example, to prevent a low priority file transfer from interfering with a connection established to carry real-time voice or video data.
The primary method of providing ATM switched virtual circuit services to devices that do not have native ATM support is to install routers between the IP network and the ATM network that have the ability to generate ATM switched virtual circuits on a per IP flow basis. The problems with this approach are: (1) possible destination IP addresses need to be provisioned in the router ahead of time, and (2) it is not possible to define, on an IP flow basis, which IP flow should get the ATM switched virtual circuit service and which should get IP best efforts service. If a destination address is provisioned in the ATM interworking router, then all connections to that destination address will require an ATM switched virtual circuit.